NEW YORK — More than 1,800 flights remain delayed or cancelled in the aftermath of a massive weekend blizzard that slammed into the eastern U.S., wreaking havoc on travel in the nation’s busiest cities.

But that was a big improvement from the 3,100 flights that failed to take off Friday and 4,511 grounded on Saturday during the height of the storm.

On Monday, airports in the New York City and Washington D.C. metro areas were the hardest hit. Newark Liberty International lists 254 cancelled flights and 13 delays as of Monday morning, the most of any U.S. airport, according to the flight tracking service FlightAware. Meanwhile, LaGuardia lists 149 cancelled flights and 10 delays with John F. Kennedy airport listing 45 cancellations and 20 delays.

In Washington D.C., Washington Dulles International listed 128 cancellations and 3 delays, making it the third-worst affected airport in the nation. Reagan National had 115 cancellations. Baltimore/Washington International listed 74 cancellations and 4 delayed.

United Airlines, which is owned by United Continental Holdings Inc., suffered the brunt of cancellations for major airlines as it has key hubs at both Newark Liberty and Washington Dulles. There are already more than 200 flight cancellations for Tuesday, with the bulk from United Airlines’ regional carrier United Express at Washington Dulles.

Many airports are now facing the difficult task of clearing the sheer amount of snow, but relocating it is posing a lingering problem. Delta Air Lines, for example, had at least four gates inaccessible at LaGuardia because of snow on the ramp.

The storm dropped snow from the Gulf Coast to New England, with near-record snowfalls tallied from Washington, D.C. to New York City. At least 31 people have died as a result of the snowstorm. The deaths occurred in car accidents, from carbon monoxide poisoning, and from heart attacks while shoveling snow